The employment of gas activated intra-aortic balloons is at the present time an accepted therapeutic method for mechanically assisting the heart. The balloon is inserted into the proximal portion of the descending thoracic aorta and is inflated and deflated with gas in synchoronism with heart action. Therapeutic benefit is derived from decreasing the workload of the heart and from augmenting perfusion of the coronary arteries during diastole. The number of applications, in the United States alone, is in excess of 18,000 per year. With the advent of the so-called "percutaneous" type balloon, the membrane of the balloon is significantly thinner than in the older types. This thinness and the necessity of wrapping the balloon by winding it up on itself for percutaneous insertion and thereafter unwinding it in the aorta have increased the risks of balloon failure caused by any weaknesses introduced during manufacture, by damage caused by intra-aortic plaques, or by inappropriate medical techniques. However, a balloon failure such as a leak, and in particular a rupture, which allows the inflating gas to enter the bloodstream, can cause a disastrous gas embolism. The prior art, the detection means, which are incorporated into existing intra-aortic balloon drive and control systems, are based on detecting with varying degrees of sensitivity--a loss of drive gas, i.e., after gas has escaped. Equally unsatisfactory is "detection" by personnel observing blood appearing in the pneumatic drive line.
The present invention is directed to a method of and an apparatus for providing a direct, intra-corporeal detection of intra-aortic balloon leaks which when used in conjunction with an automatic shutdown and an alarm system is designed to prevent gas escape and consequent gas embolism. In addition, the present method and apparatus also provides the means for direct monitoring of the inflation and deflation of the balloon operation, a feature presently not available in balloon drive systems.